The electronic structure of III-V zinc blend Gallium Phosphide nanocrystals is investigated using ab-initio density functional theory coupled with large unit cell for the core and surface parts. Two kinds of cells are investigated: multiple Bravais and multiple primitive cells. The results show that both energy gap and valence band width depend on the shape of the nanocrystal. Results also revealed that most electronic properties converge to some limit as the size of the large unit cell increases. Furthermore, the results have shown that the cohesive energy is decreasing with increasing size of nanocrystals. The core part is more degenerate, with larger energy gap and smaller valance and conduction bands than the surface.